A National Security Agency civilian employee resigned last month after telling the FBI he had inadvertently let former contractor Edward Snowden use his password to access information he was not authorised to see, according to a NSA memo sent to Congress.
The NSA told the Senate Judiciary Committee in the memo that two other workers affiliated with the NSA, including an active duty military member and an unidentified contractor, had also been "implicated" in the matter.
The memo said the contractor and military member had been stripped of their access to classified information and secure workspaces last August.
The existence of the memo, dated February 10 and marked "Unclassified/For Official Use Only" was first reported on the website of NBC News.
Reuters reported in November that Snowden had used login credentials and passwords provided unwittingly by colleagues at a spy base in Hawaii to gain access to some of the classified material he leaked to the media.
The NSA says it drew up the memo sent this week to update the Judiciary Committee on steps the agency had taken to hold people accountable for the role they might have had in Snowden's unauthorised disclosures.
The civilian in question first admitted on June 18 that he had given his login credentials, in the form of a "Public Key Infrastructure certificate," to Snowden, the memo said.
The memo said that when the unnamed civilian NSA employee gave the login information to Snowden, he knew it would give him access on a system known as NSANet to which Snowden otherwise was denied access.
At Snowden's request, the NSA worker entered his password into Snowden's computer terminal.